One second after...what if that happened here?

[xflip14]

in the book it was multiple hitting all over the us and it never says who launched them...it was a fiction book also back on the random ammo point lets say you need to trade some of it..if you only got 10mm and the guy with all the food needs 9....kinda unhelpful just more food for thought about what to stack up on

[WRW]

Ok the situation is (like in the book) an EMP goes off, fries everything electrical, cell phones, cars, lights we have nothing...now what. do you have the provisions to get past the immediate crazyness, what about the knowledge to get by in the long run?

I dunno. Haven't read the book, but this was the premise.

No problem. I'm just trying to understand how such an EMP could be generated and it would matter much more than 15 mins. The only way I know of to generate an EMP that large is a nuclear dentonation at altitude. The Starfish Prime test was a 1.44MT bomb. While tests create massive bombs, actual deployed warheads are much smaller, usually between 100-500KT. About 1/3 what the EMP test at best.

http://en.wikipedia.org/wiki/Electromagnetic_pulse
http://en.wikipedia.org/wiki/Nuclear_weapon_yield

Don't get me wrong, 500KT is still crazy powerful and with modern knowledge you could get a similar EMP with a lot less yield than 1.44MT. However, that is a US weapon. Anything from NK or Iran or anyone beside a first world country is likely to be much smaller.

What I'm having trouble comprehending is the situation where a nuke is air burst above US soil and we sit around doing nothing. Seems to me that war would go hot very quickly (heck it did with the EMP burst) and it wouldn't matter much anymore.

While it shouldn't affect appliances, a geomagnetic storm could wreak havoc with the power grid and create many of the problems addressed. Current thinking is that that will happen.

[Jim]

I think the circumstances are going to dictate how "would be" robbers will act. My wife and I are in the country. WAY out in the country. We're more likely to get a visit from neighbors on a 4 wheeler or horse back checking on us/ offering help than an assault. I think the closer you get to civilization density, the more trouble you'll encounter. Something else, too: People out here, even the stupid ones that might contemplate a stupid move, know that behind every front door will be a 12 gauge pump or automatic, a bolt action deer rifle and a handgun. Plus a complement of family knowledgeable in the use thereof. Plus, out here, people know more about surviving than those "in the city". The city folk won't have much means of getting out here and won't know where to go to get help either.
I'm fairly isolated, but I like it and I'll stick with what I have and where I am.

[zephyp]

It's not the satellites but that little handheld dickens that I was thinking about.

Its quite simple to shield electronic components. Buy an extra GPS and make a shielded storage box...after the event you're good to go...plenty of info on the net for making your own box...

[WRW]

It's not the satellites but that little handheld dickens that I was thinking about.

Its quite simple to shield electronic components. Buy an extra GPS and make a shielded storage box...after the event you're good to go...plenty of info on the net for making your own box...

That'd work. A tin foil hat for your spare GPS.
Or get the "solar powered" one I mentioned earlier and forget the shielding.

[gunderwood]

It's not the satellites but that little handheld dickens that I was thinking about.

Its quite simple to shield electronic components. Buy an extra GPS and make a shielded storage box...after the event you're good to go...plenty of info on the net for making your own box...

That'd work. A tin foil hat for your spare GPS.
Or get the "solar powered" one I mentioned earlier and forget the shielding.

Shielding is possible (a lot of military HW goes through EMP testing) and while the concept is simple, implementing it correctly can be difficult. The design of the shielding is frequency dependent and I'm not sure the designs on the Internet have taken this into account. Even if your electronics survived, getting power is a real problem. The grid is not shielded, nor is it practical to do so, but the physical infrastructure should survive. However, the design of the transmission grid *should* prevent any surge reaching the actual plant, but that causes its own problem.

The grid is a tightly controlled system. The power which a power plant puts out much match the transmission loses and the accumulative loads. This is accomplished by frequency control. The power plants "generators" essentially spin at a constant rate which provides the 60Hz. If new loads come on line, the frequency of the system will drop down because the output of the generator is less than what the system demands. Practically, that means that energy stored in the momentum of the generator is converted...is slows down which changes the frequency. The plants controllers will then apply more fuel to the generator which will spin up until 60Hz is achieved again. This generally works because the generators are massive and the change in loads is small. Certain industrial customers must work with the power company to turn on equipment in a particular order or with a certain delay or even just advanced notice because of the large changes in power consumption.

There are two main transmission grids, one for the east coast and one for the west coast. Literally, every generator on each grid is running at the exact same rate. I.e. they are all connected.

The problem with an EMP is you suddenly remove all loads (if the transmission grid protects itself like it is designed too) and the generator is likely to damage itself. Unlike traditional power failures which cascade as loads go off-line (which causes the same problem as an EMP, but slower and on a smaller scale), an EMP would do all of the loads virtually instantaneously. This assumes that the plant was EMP protected which I don't think they are. That would force the main generator to go off-line which is a huge problem. All of these modern power plants require power to get started. Usually they keep a simple, low output generator around to "jump start" the main plant. That generator is way to small to do anything useful but start the main plant.

However, jump starting the main plant is a difficult and long process. Generally these large plants take at least 24hrs to do all of the pre-start processes and if it doesn't start, you start all over again. This is why when plants go off-line you get blackouts measuring in days, not hours. They are rare because of how the grid protects itself. Furthermore, just getting one plant on-line isn't enough. Expect that they purposefully disconnect all non-emergency loads if they get the plant back up and running.

Given all of that the residual effects of an EMP would make power transmissions hazardous or practically impossible. With isolation transformers you *might* be able to get some power transmission going safely. However, if you don't have one of those already and shield it from the initial EMP (and aren't a critical service), you're SOL. Isolation transformers are pretty simple, so it is possible an unshielded one could survive, but you'd have to talk to an EMP expert.


How would a solar powered device help you? Both require shielding to survive. An EMP induces voltage into anything that conducts. That induced voltage causes very short, but high currents to flow which is what kills the electronics. You don't need any power source to be attached to the electronics for this to happen. If the residual storms are strong enough they would just fry either device once you took it out of the shielded box.


EMPs are generated with all nuclear devices. However, there are canceling effects that happen shortly after it is generated when it is done close to the earth. To get the EMP scattered you must detonator high enough in the atmosphere so that the earths magnetic field scatters it before the canceling effects happen. (That is the simple explanation) Usually altitudes between 100-300 miles are considered ideal for an attack against the USA. Other places are different due to the variances of the earths magnetic field.

Detonating a large nuclear device 100-300 miles up is a non trivial exercise of which only a handful of countries are capable of doing and none are capable of doing without us knowing who did it. You can't hide a ICBM launch these days. Within minutes we already know who launched it, where it is going to hit, and our missiles are on their way to retaliate. You would have to take out a serious number of satellite assets and other earth assets before you could hide such a thing. Nukes on satellites *might* be possible, but extremely risky and probably impractical.

Furthermore, the US military has assets in low earth orbit (LEO) and has held that any attack on them is an attack against US forces. Nukes at 100-300 miles would take out a bunch of them. Also, the residual magnetic storms would possibly cause satellite comms issues. The military has ways of communicating with our assets around the world (i.e. probably not effected by the air burst), but anything orbiting through those storms or trying to communicate through them is in trouble. GPS birds would likely survive, but the extra noise would probably cause most civilian receivers to not work. The only comfort would be that GPS sats overhead are not very useful for calculating your position...you need birds towards the horizon. There is a chance, if shielded to survive the initial EMP, that a civilian GPS could work. I wouldn't hold my breath though.

GPS is the least of your worries. Nothing would work. No cars, no computers, no farming equipment, not water purification, nothing. If you don't already have land you are farming, access to a natural water source, etc. you're SOL. If an EMP attack of that scale happens the US becomes worse than a third world country overnight. The infrastructure is gone. We lack the basic tools we would need because we have replaced them with advanced tools. We lack the factories to make the advanced tools. Much of the knowledge needed will have been killed off. Etc. Etc.

Generally, an EMP isn't something I've prepared for because I can't figure out how anyone could do it without starting WWIII.

[WRW]

Yeah, solar powered GPS...accurate clock and sextant.

I don't see the circuits needing shielding here.

[gunderwood]

Yeah, solar powered GPS...accurate clock and sextant.

I don't see the circuits needing shielding here.

Any electronics, regardless of power source get fried if the EMP is strong enough. Even simple things like a digital watch would be toast. The actual integrated circuit gets fried. Most of the modern GPS receivers are a single chip/package solution. I.e. this usually means you solder them to a board, provide power and ground and simply talk to them through a serial connection. Any decent EMP and that chip is never working again.

The clock in a GPS is derived from the satellites. That is how GPS works, highly accurate clocks measuring the delta time difference between the "same" (ignoring gold coding here) clock due to propagation delays. I.e. each satellite broadcasts its clock and since each satellite is at a different distance from you, you receive the clock pulses at different times. The satellites transmit on what is called a gold code so you can pick out which ones you are listening too. Combine that with the ephemeris and you can calculate where you are. Kind of like triangulation, but more complex. You need a base reference clock, so to get a 3d fix you need at least 4 sats (there is fancy math to around this too, but accuracy is awful). To get a really good fix you need more.

Solar cells are made the same way as ICs are. There is a highly likelihood that the solar cells would also sustain damage from an EMP. ICs which require good clocks like processors and GPS will be toast in a lower intensity EMP.

[zephyp]

The grid is a tightly controlled system.

Yeah, right...

WRT to shielding being difficult - its not. Most of the laptops purchased on DOD contracts these days are shielded against EMP...read a couple of readily available Internet articles for making your own storage container. The "old days" shielding was quite expensive but not any more...

And, for something like GPS - the grid isnt required. On orbit assets are powered organically and hand held GPS units run on batteries...the only problem is if your GPS batteries are the rechargeable kind. If thats the case simply use a generator which isnt affected by an EMP pulse...oh, and store the recharger too...

[zephyp]

@gunderwood - some electronics are immune to EMP...ICs are the big things vulnerable...tube technology gets a free pass.

[gunderwood]

@gunderwood - some electronics are immune to EMP...ICs are the big things vulnerable...tube technology gets a free pass.

No it isn't. It is just less vulnerable. When they did the Starfish prime, some of the tube base equipment was destroyed.

http://en.wikipedia.org/wiki/Electromag ... uclear_EMP

Older, vacuum tube (valve) based equipment is much less vulnerable to EMP than newer solid state equipment; Soviet Cold War–era military aircraft often had avionics based on vacuum tubes due both to limitations in Soviet solid-state capabilities and a belief that the vacuum-tube gear would survive better.

Although vacuum tubes are far more resistant to EMP than solid state devices, other components in vacuum tube circuitry can be damaged by EMP. Vacuum tube equipment actually was damaged in 1962 nuclear EMP testing. Also, the solid state PRC-77 VHF manpackable 2-way radio survived extensive EMP testing.[19] The earlier PRC-25, nearly identical except for a vacuum tube final amplification stage, had been tested in EMP simulators but was not certified to remain fully functional.

Anything that conducts is potentially toast. Anything an EMP can induce a voltage into is potentially dead.

The grid is a tightly controlled system.

Yeah, right...

Yes, it is. The frequency variation of the US power grid is extremely small. If you understand what the quote below says, it literally means that the power to turn on your light bulb is isn't available until you turn it on. At which point the system alters its configuration and supplies just enough power for the increased load.

The primary reason for accurate frequency control is to allow the flow of alternating current power from multiple generators through the network to be controlled. The trend in system frequency is a measure of mismatch between demand and generation, and so is a necessary parameter for load control in interconnected systems.

Frequency of the system will vary as load and generation change. Increasing the mechanical input power to a synchronous generator will not greatly affect the system frequency but will produce more electric power from that unit. During a severe overload caused by tripping or failure of generators or transmission lines the power system frequency will decline, due to an imbalance of load versus generation. Loss of an interconnection, while exporting power (relative to system total generation) will cause system frequency to rise. AGC (automatic generation control) is used to maintain scheduled frequency and interchange power flows. Control systems in power plants detect changes in the network-wide frequency and adjust mechanical power input to generators back to their target frequency. This counteracting usually takes a few tens of seconds due to the large rotating masses involved. Temporary frequency changes are an unavoidable consequence of changing demand. Exceptional or rapidly changing mains frequency is often a sign that an electricity distribution network is operating near its capacity limits, dramatic examples of which can sometimes be observed shortly before major outages.

Frequency protection relays on the power system network sense the decline of frequency and automatically initiate load shedding or tripping of interconnection lines, to preserve the operation of at least part of the network. Small frequency deviations (i.e.- 0.5 Hz on a 50 Hz or 60 Hz network) will result in automatic load shedding or other control actions to restore system frequency.

Smaller power systems, not extensively interconnected with many generators and loads, will not maintain frequency with the same degree of accuracy. Where system frequency is not tightly regulated during heavy load periods, the system operators may allow system frequency to rise during periods of light load, to maintain a daily average frequency of acceptable accuracy.
http://en.wikipedia.org/wiki/Utility_frequency

WRT to shielding being difficult - its not. Most of the laptops purchased on DOD contracts these days are shielded against EMP...read a couple of readily available Internet articles for making your own storage container. The "old days" shielding was quite expensive but not any more...

The level of induced voltage is important. Yes, the military buys laptops that are EMP shield, but they are no where near as shielded as something like Air Force One or a warship. Basic EMP shielding is not hard, but to protect against the event described here it is very hard. We spend big bucks making our warships and such reasonably EMP proof, but even they are not 100% protected.

And, for something like GPS - the grid isnt required. On orbit assets are powered organically and hand held GPS units run on batteries...the only problem is if your GPS batteries are the rechargeable kind. If thats the case simply use a generator which isnt affected by an EMP pulse...oh, and store the recharger too...

Of course the GPS satellites are powered by batteries, which are recharged from solar cells. Assuming your GPS survives, how long can it run on a single charge? Have you factored in that most NiCd, NimH, alkaline self discharge? Lithium batteries aren't sealed from the air and degrade regardless if they are used or not, charged or not. If you store it, you won't have a full charge when you need it.

The generator would need to be stored in a box too. The initial EMP is short, but the resulting magnetic storms would not be. Just like periods of high sun spot activity we have sat comms issues.

Think of EMP protection like a bullet proof vest. We know the vests are not totally bullet proof, but stand a high probability of protecting you against the rated rounds. Wear a Level II/IIA vest and it will stop most pistol rounds. It will not stop a knife or rifle round. Even with a Level IV vest/plates, good luck stopping a 50BMG API round. There are various levels of protection based on the threat. Just because something says it is EMP shielded or you take steps to shield it doesn't mean it is against the level of threat you are trying to protect against.

[gunderwood]

As more proof that even simple things that conduct can be destroyed by an EMP:

Starfish Prime also made those effects known to the public by causing electrical damage in Hawaii, about 1,445 kilometres (898 mi) away from the detonation point, knocking out about 300 streetlights, setting off numerous burglar alarms and damaging a telephone company microwave link.
http://en.wikipedia.org/wiki/Electromagnetic_pulse

[zephyp]

Ok, not immune but for the sake of argument it virtually is...tubes that is...when you say the grid is tightly controlled I took that to mean tightly as in security wise...and once again yeah right...controlled to a standard - yes...

Ok, while I was out watering I thought about this. EMP is kinda like a voltage surge on steroids. So any of the common components today that we hook up to a surge suppressor are likely targets. The primary reason is that the electronics of computers, TVs, etc (that is integrated chips) are very susceptible to voltage fluctuations. A computer doesnt have to be turned on to get zapped by a big surge. I'm sure some of you know this from experience. Most of todays electronics are IC based hence the big concern. Yes, tube technology can be affected but my guess is if its turned off it would likely survive. And, contrary to what Garrett said not everything electrical is affected. For instance, the electrical wiring in your home will still be good. I can easily name half a dozen electrical appliances that will still be functional unless they are computer controlled...stove, toaster, coffee pot, can opener, knife, etc...the only problem is that the "tightly controlled" grid Garrett spoke of will most likely be useless...and, a case in point...EMP doesnt indiscriminately destroy everything electrical hundreds of miles in every direction...where is the Enola Gay right now? And yes, I know "someone" will say that it could have been damaged by EMP had it been at a lower altitude and closer to the blast...true but she flew on home to a victory parade...btw, modern military aircraft are shielded (hardened)...

But having said all that, a properly executed EMP event over the US would screw up the rest of our lives for good...thank God we arent all carryin fancy electronic guns like in the movie Aliens...

[gunderwood]

Ok, not immune but for the sake of argument it virtually is...tubes that is...when you say the grid is tightly controlled I took that to mean tightly as in security wise...and once again yeah right...controlled to a standard - yes...

Ok, while I was out watering I thought about this. EMP is kinda like a voltage surge on steroids. So any of the common components today that we hook up to a surge suppressor are likely targets. The primary reason is that the electronics of computers, TVs, etc (that is integrated chips) are very susceptible to voltage fluctuations. A computer doesnt have to be turned on to get zapped by a big surge. I'm sure some of you know this from experience. Most of todays electronics are IC based hence the big concern. Yes, tube technology can be affected but my guess is if its turned off it would likely survive. And, contrary to what Garrett said not everything electrical is affected. For instance, the electrical wiring in your home will still be good. I can easily name half a dozen electrical appliances that will still be functional unless they are computer controlled...stove, toaster, coffee pot, can opener, knife, etc...the only problem is that the "tightly controlled" grid Garrett spoke of will most likely be useless...and, a case in point...EMP doesnt indiscriminately destroy everything electrical hundreds of miles in every direction...where is the Enola Gay right now? And yes, I know "someone" will say that it could have been damaged by EMP had it been at a lower altitude and closer to the blast...true but she flew on home to a victory parade...btw, modern military aircraft are shielded (hardened)...

But having said all that, a properly executed EMP event over the US would screw up the rest of our lives for good...thank God we arent all carryin fancy electronic guns like in the movie Aliens...

Ground burst nukes (or close enough) still create an EMP, but it is not scattered like an air burst is. To be an air burst or high altitude burst requires them to be miles above the earths surface. The Enola Gay was not effected because it was a low altitude burst and generally the EMP only goes a few miles at best.

The EMP induces a voltage according to Faraday's law. Because of the potential, a current is induced in all things that are conductive. Thus, yes, everything that is conductive is affected. Not everything is destroyed and I've never claimed that. Much like a lightening strike, strange things happen, but you can't count on them going your way.

The E1 pulse is the very fast component of nuclear EMP. The E1 component is a very brief but intense electromagnetic field that can quickly induce very high voltages in electrical conductors. The E1 component causes most of its damage by causing electrical breakdown voltages to be exceeded. E1 is the component that can destroy computers and communications equipment and it changes too fast for ordinary lightning protectors to provide effective protection against it.

The E1 component is produced when gamma radiation from the nuclear detonation knocks electrons out of the atoms in the upper atmosphere. The electrons travel in a generally downward direction at relativistic speeds (more than 90 percent of the speed of light). This essentially produces a large pulse of electrical current vertically in the upper atmosphere over the entire affected area. This electrical current is acted upon by the Earth's magnetic field to produce a very large, but very brief, electromagnetic pulse over the affected area.
http://en.wikipedia.org/wiki/Electromagnetic_pulse

Many nuclear detonations have taken place using bombs dropped by aircraft. The B-29 aircraft that delivered the nuclear weapons at Hiroshima and Nagasaki did not lose power due to damage to their electrical or electronic systems. This is simply because electrons (ejected from the air by gamma rays) are stopped quickly in normal air for bursts below roughly 10 km (about 6 miles), so they do not get a chance to be significantly deflected by the Earth's magnetic field (the deflection causes the powerful EMP seen in high altitude bursts), thus the limited use of smaller burst altitudes for widespread EMP.
http://en.wikipedia.org/wiki/Electromagnetic_pulse

For a surface burst, absorption of gamma rays by air would limit the range of gamma ray deposition to approximately 10 miles, while for a burst in the lower-density air at high altitudes, the range of deposition would be far greater.
http://en.wikipedia.org/wiki/Electromagnetic_pulse

Older vacuum tube technology required higher voltages and currents to destroy. That is why it is less vulnerable. No magic to it. Modern ICs are vulnerable because it doesn't take much induced voltage or current to break them. An EMP doesn't choose what it induces a voltage in, rather anything that is conductive will have a voltage induced in it. Yes, even wires will be affected. If you remember the Starfish Prime test quote I gave earlier, incandescent lights had to be replaced. The induced voltage causes sufficient current to flow that it destroyed the bulb. Turning a vacuum tube off doesn't magically make it impervious to an EMP. What it does do is raise the voltage required to be induced to damage it.

Yes, even things like coffee pots, refrigerators, etc. have ICs in them...generally small micro-controllers.

The E2 field is very much like lighting and generally it is assumed that most lighting protection would be sufficient to protect against all reasonable E2 fields. There is also an E3 field which is very much like a solar flare, but E1 is the field most people are referencing when talking about EMP damage.

The E2 component of the pulse has many similarities to the electromagnetic pulses produced by lightning. Because of the similarities to lightning-caused pulses and the widespread use of lightning protection technology, the E2 pulse is generally considered to be the easiest to protect against.

The E3 component of the pulse is a very slow pulse, lasting tens to hundreds of seconds, that is caused by the nuclear detonation heaving the Earth's magnetic field out of the way, followed by the restoration of the magnetic field to its natural place. The E3 component has similarities to a geomagnetic storm caused by a very severe solar flare.[17][18] Like a geomagnetic storm, E3 can produce geomagnetically induced currents in long electrical conductors, which can then damage components such as power line transformers.
http://en.wikipedia.org/wiki/Electromagnetic_pulse

The grid is tightly controlled from a control theory standpoint. Nothing about the discussion about an EMP burst 100 miles above the earths surface has anything to do with physical security. It has everything to do with possibly completely FUBARing all the controllers. It also matters since the transmission grid is so tightly coupled along the three grids (I previously forgot Texas) that a cascading shutdown would happen if any significant portion of the grid when down instantly.

Edit: I should add that when the previous quote talks about damaging transformers that a transformer is basically two big coils of wire...the currents aren't likely to be high enough to damage the actual wire.

[Reverenddel]

I quote Hank Williams Jr.

"A country boy can survive..."